This invention relates generally to surge protection and more particularly to surge protectors for hardware receiving signals via coaxial cable.
It is well known to provide electronic devices with surge protectors, lightning arrestors and bypass circuitry to protect the device from surges on the power input and signal input. Surge protectors, lightning arrestors and bypass circuitry are shown in Jones et al., U.S. Pat. No. 6,236,551B1, issued May 22, 2001; Jones et al. U.S. Pat. No. 6,115,227, issued Sep. 5, 2000; Jones et al., U.S. Pat. No. 6,061,223, issued May 9, 2000; Knoedl, Jr. et al, U.S. Pat. No. 5,987,335, issued Nov. 16, 1999; Zahlman et al., U.S. Pat. No. 5,963,413, issued Oct. 5, 1999; Joulie et al., U.S. Pat. No. 5,875,090, issued Feb. 23, 1999; Girard, U.S. Pat. No. 5,831,808, issued Nov. 3, 1998; Kashara et al., U.S. Pat. No. 5,790,362, issued Aug. 4, 1998; Minich, U.S. Pat. No. 5,790,361, issued Aug. 4, 1998; Mansfield et al., U.S. Pat. No. 5,652,690, issued Jul. 29, 1997; Shirakawa et al., U.S. Pat. No. 5,283,709, issued Feb. 1, 1994; Igarashi, U.S. Pat. No. 4,644,441, issued Feb. 17, 1987; Cline, U.S. Pat. No. 4,486,805, issued Dec. 4, 1984; Smith, U.S. Pat. No. 4,447,848, issued May 8, 1984; Block, U.S. Pat. No. 4,409,637, issued Oct. 11, 1983; Franchet, U.S. Pat. No. 4,355,345, issued Oct. 19, 1982; Bitsch et al., U.S. Pat. No. 4,314,303, issued Feb. 2, 1982; Miske, Jr., U.S. Pat. No. 3,663,856, issued May 16, 1972; McStrack, U.S. Pat. No. 3,577,032, issued May 4, 1971; Stetson, U.S. Pat. No. 3,504,226, issued Mar. 31, 1970; Loy, U.S. Pat. No. 1,987,575, issued Jan. 8, 1935; and Narans et al., U.S. Pat. No. 1,430,674, issued Oct. 3, 1922, the disclosures of which are hereby incorporated by this reference.
Jones et al., U.S. Pat. No. 6,236,551 B1 (“Jones '551”) Jones et al., U.S. Pat. No. 6,115,227 (“Jones '227”) and Jones et al., U.S. Pat. No. 6,061,223 (“Jones '223”) (“collectively the Jones patents”) are a family of patents issuing on the parent and continuations thereof and therefore provide the same disclosure. The Jones Patents show a connector for coaxial lines having a capacitive element and a spiral shaped inductive element designed to provide lightning protection while matching impedance of the incoming line. Thus, it is well known to configure and design connectors to match the impedance of incoming lines. It is also well known to utilize inductive and capacitive elements in a lightning surge protection device to tune the connector as shown in the Jones Patents, Block and Minich. Such devices use impedance matching techniques so that the lumped inductances and capacitances of the various components and structures of the connector, when taken together, exhibit the same characteristic impedance as the transmission line to which it is connected. However, such devices typically include multiple parts requiring calibration and tuning and often incorporate time intensive or complicated assembly techniques.
The present invention comprises one or more of the following features or combinations thereof. A lightning surge protection device is provided that is simple to manufacture and assemble yet provides lightning surge protection while remaining transparent to transmitted signals.
The surge protector for a signal receiving device configured to receive signals via a transmission line includes an inner conductor having a capacitance, an outer conductor, insulating material electrically insulating the inner conductor from the outer conductor and an inductor inductively coupling the inner conductor and outer conductor. Illustratively, the outer conductor is formed of two components that are coupled together. To aid in assembly of the lightning surge protector, the outer conductor may be formed from a case and a plug that is frictionally secured within the case. The inductor is solderlessly connected to the inner conductor and the outer conductor. The inner conductor includes a first conductive portion and a second conductive portion. Dielectric material separates the first conductive portion from the second conductive portion. The dielectric material may be injection molded to the first and second conductive portions of the inner conductor or may be a separate dielectric portion configured to snap onto the conductor portions. Illustratively, the dielectric portion partially encapsulates the first and second conductors to mechanically secure the conductors together. The dielectric material may be injection molded simultaneously with the insulating material to the first and second conductive portions to form an insulated inner conductor module. The insulating material includes a first insulating material insulating the first conductive portion from the outer conductor and a second insulating material insulating the second conductive portion from the outer conductor.
To reduce assembly costs, the inner conductor may include an inductor-receiving hole formed therein to receive a portion of the inductor therein to electrically and mechanically couple the inductor to the inner conductor. To facilitate solderless connection of the inductor to the inner conductor the inductor may include a bent portion which when inserted in the inductor-receiving hole is deformed so as to generate a restorative force-acting to couple the inductor to the inner conductor. To reduce the cost of manufacturing the surge protector, the conductive portion, case and plug may each be cast.
A method of manufacturing such a surge protection device is provided. The method comprises the steps of providing an insulated inner conductor, an inductor and an outer inductor which are assembled. The provided insulated inner conductor includes a first insulating portion coupled to a first conductor configured to be coupled to a signal carrying component of the signal receiving device and a second insulating portion coupled to a second conductor configured to be coupled to the inner conductor of the coaxial line. The first and second conductors are capactively coupled to one another. The provided outer conductor is a two component outer conductor. Each component of the outer conductor is configured to include a cavity sized to receive one of the first and second insulating portions therein and is configured to couple to the other component of the outer conductor. One component of outer conductor is configured to be coupled to an outer conductor of the coaxial line. The other component is configured to be coupled to a ground of the signal receiving device. The first insulating portion of the insulated inner conductor is inserted into the cavity of a selected one of the components of the outer conductor. The inductor is coupled between the insulated inner conductor and the selected one of the components of the outer conductor. The second insulating portion of the insulated inner conductor is inserted into the cavity of the other component of the outer conductor. The two components of the outer conductor are coupled whereby the inner conductor is electrically insulated from, but inductively coupled to, the outer conductor. The provided insulated inner conductor includes dielectric material mechanically and capacitively coupling the first conductor to the second conductor. The first insulating portion and the second insulating portion may be simultaneously molded to the first and second conductors. Similarly, the first insulating portion, the second insulating portion and the dielectric material may be simultaneously molded to the first and second conductors.
The inductor may include an inner conductor end and an outer conductor end, the provided insulated inner conductor includes an inductor-receiving hole, the selected component of the outer inductor includes an inductor-receiving hole and wherein the coupling the inductor step includes the steps of inserting the inner conductor end into the inductor-receiving hole of the insulated inner inductor and inserting the outer conductor end into the inductor-receiving hole of the selected component of the outer conductor. The outer conductor end of the inductor may be inserted into the inductor-receiving hole of the selected component of the outer conductor simultaneously with the insertion of the first insulating portion of the insulated inner conductor into the cavity of a selected one of the components of the outer conductor.
To facilitate solderless assembly of the inductor to the inner conductor, the inner conductor end of the inductor may include a bent portion so that insertion of the inner conductor end into the inductor-receiving hole of the inner conductor step causes deformation of the bent portion to generate a restorative force acting to couple the inductor to the inner conductor. Similarly, the outer conductor end of the inductor may be staked into the inductor receiving hole.
One component of the provided two component outer conductor may be a case having a cavity therein and the other component of the provided two component outer conductor may be a plug configured to be received in the cavity of the case. The plug may be the selected component. The first and second conductors of the insulated inner conductor and/or the two component of the outer conductor may be cast.
By pressing the two components of the outer conductor together, assembly costs may be reduced. Assembly costs may be further reduced by simultaneously inserting the second insulating portion of the insulated inner conductor into the cavity of the other component of the outer conductor while coupling the two components of the outer conductor.
Thus, the surge protector components are configured to generate modules and subassemblies facilitating assembly by pressing modules and subassemblies together.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments exemplifying the best mode of carrying out the invention as presently perceived.